I have an electric guitar. It has a 4 position switch that selects which
of the three pickups, or all of them. There is a piece of metal that
sticks up, which is supposed to have a knob on it. Knob was missing.
Besides appearance, that metal shaft is sharp and dont feel good on the
hand.

But this is not your typical round shaft, it's a flat piece of metal
about 1/4" wide and 1/32 inch thick. So the knob will have a slit in it.
The guitar is a Silvertone from probably the 1970s, so I wont likely
find an original knob. But I am not all that picky about getting an
original, as long as I can get something that fits.

I did call a music store and was told that they will check what they
have, but said he doubts they have anything. (Will call me back). So it
looks like I am gonna have to fidn something at an electronics store or
ebay. My question is *What do you call this sort of knob*? I dont know
what words to search for.